About This 12 Week Half Marathon Training Plan
A 12 week half marathon training plan is the sweet spot for most runners preparing for 13.1 miles. This 3-month program provides enough time to build endurance safely while keeping you focused and motivated throughout the entire training cycle.
Why 12 Weeks is the Perfect Duration
The 12-week timeline offers unique advantages:
- Not too short, not too long: Ideal balance of preparation and motivation
- Fits life schedules: 3 months is manageable for busy professionals
- Progressive buildup: Safe 10% weekly mileage increases
- Proven effectiveness: Most popular duration among successful half marathoners
- Flexible start times: Register for races 3 months out
- Sustainable commitment: Long enough to see real fitness gains
Who Should Use a 12 Week Half Marathon Plan?
This plan is ideal if you:
- Can currently run 3-4 miles comfortably
- Have been running consistently for at least 1-2 months
- Want to complete your first half marathon with proper training
- Have completed a 10K race and want to step up
- Are experienced runners returning after a break
- Want a structured, proven approach that works
- Have 3 months until race day
12 Week Half Marathon Training Plan Structure
Our AI-personalized 12 week plan follows this progression:
Weeks 1-3: Base Building Phase
- Weekly mileage: 12-15 miles
- Long run: 4-6 miles
- Focus: Establish consistent running routine
- Workouts: Mostly easy runs, 1 slightly longer run on weekend
Weeks 4-6: Endurance Development
- Weekly mileage: 15-20 miles
- Long run: 6-8 miles
- Focus: Build aerobic endurance
- Workouts: Easy runs + 1 tempo run per week
Weeks 7-10: Peak Training
- Weekly mileage: 20-25 miles
- Long run: 8-11 miles (peak at 10-11)
- Focus: Race-specific endurance
- Workouts: Long runs + tempo runs + easy runs
Weeks 11-12: Taper & Race
- Weekly mileage: 15-18 miles (decreasing)
- Long run: 6 miles (week 11), 3-4 miles (week 12)
- Focus: Rest, recover, maintain fitness
- Workouts: Shorter easy runs + race day!
Sample Week from a 12 Week Half Marathon Plan
Here's what week 8 might look like (peak training):
- Monday: Rest or easy cross-training (30 min)
- Tuesday: Easy run 4 miles at conversational pace
- Wednesday: Tempo run - 1 mile warm-up, 3 miles at comfortably hard pace, 1 mile cool-down (5 miles total)
- Thursday: Easy run 3-4 miles
- Friday: Rest day
- Saturday: Long run 10 miles at easy pace
- Sunday: Easy recovery run 3 miles or rest
- Total: 24-25 miles for the week
Key Workouts in Your 12 Week Plan
Long Runs (Most Important!)
- Start at 4-5 miles, build to 10-11 miles
- Run at easy, conversational pace
- Done once per week, typically Saturday or Sunday
- Practice race day nutrition and hydration
- Builds endurance and mental toughness
Tempo Runs
- 3-5 miles at comfortably hard pace
- Improves lactate threshold
- Typically done mid-week (Wednesday or Thursday)
- Pace should be challenging but sustainable
Easy Runs
- 3-5 miles at comfortable pace
- Should be able to hold full conversation
- Most important for building aerobic base
- Don't skip these - they're crucial!
12 Week vs Other Durations
| Factor | 8 Weeks | 12 Weeks | 16 Weeks |
|---|---|---|---|
| Starting base needed | 15+ mi/wk | 8-12 mi/wk | 5-8 mi/wk |
| Weekly increase | 12-15% | 10% | 8% |
| Injury risk | Higher | Moderate | Lower |
| Best for | Experienced | Most runners | Beginners |
| Popularity | Common | Most popular | Conservative |
Training Tips for Success
- Follow the 10% rule: Never increase weekly mileage by more than 10%
- Take rest days seriously: Your body adapts and gets stronger during rest
- Run most miles easy: 80% of your running should be at conversational pace
- Don't skip the taper: Weeks 11-12 are crucial for race day performance
- Practice race day nutrition: Test gels/chews during long runs
- Get proper shoes: Visit a running specialty store for fitting
- Cross-train wisely: Swimming, cycling, or yoga on rest days
- Listen to your body: It's better to skip one run than miss two weeks injured
Nutrition for 12 Week Half Marathon Training
- Daily calories: Add 300-500 calories on training days
- Carbohydrates: 55-60% of diet for energy
- Protein: 1.2-1.4g per kg body weight for recovery
- Hydration: Drink water throughout the day, not just during runs
- Pre-run fuel: Light snack 1-2 hours before running
- Post-run recovery: Carbs + protein within 30 minutes
- Long run nutrition: Practice taking energy gels at miles 5 and 9
Common Mistakes to Avoid
- Starting too fast: Begin conservatively with your base mileage
- Running too fast: Most runs should feel easy, not challenging
- Skipping rest days: Recovery is when you get stronger
- Doing too much too soon: Stick to the 10% rule
- Neglecting strength training: 2x/week prevents injuries
- Poor shoe choice: Get fitted at a specialty store
- Not tapering properly: Trust the taper - don't panic and add miles
Download as PDF
Get your complete 12 Week Half Marathon Training Plan as a beautifully formatted PDF. Print it, save it, share it with your coach!
What's Included in Your Plan
Everything you need to succeed in your training
Perfect 3-month training timeline
Progressive buildup from 12 to 25 miles per week
Long run progression: 4 miles to 10-11 miles
Weekly tempo runs to improve pace
Built-in recovery weeks every 3-4 weeks
Taper period for race day readiness
Cross-training recommendations
Nutrition and hydration guidance
Free PDF download and calendar sync
Why Choose Our 12 Week Half Marathon Training Plan?
Most popular half marathon training duration
Ideal balance of time and results
Safe progressive mileage increases
Proven by thousands of successful finishers
Fits well into busy schedules
AI-personalized to your fitness level
Works for first-timers and experienced runners
Completely free - no subscription needed
Frequently Asked Questions
Is 12 weeks enough to train for a half marathon?
Yes, 12 weeks is the most popular and effective duration for half marathon training. It provides enough time to safely build endurance while being short enough to stay motivated throughout. If you can currently run 3-4 miles comfortably, 12 weeks is perfect. Complete beginners who can't run 3 miles yet should add 4-6 weeks of base building first, or choose a 16-week plan.
How many miles per week in a 12 week half marathon plan?
A typical 12 week half marathon plan starts at 12-15 miles per week and peaks at 20-25 miles per week around week 9-10. Beginners stay closer to 20 miles at peak, while more experienced runners might reach 25-30 miles. The exact mileage is personalized based on your current fitness level and goals. Our AI coach calculates the optimal weekly mileage for you.
What should my long run be in week 12?
Week 12 is race week, so your long run should only be 3-4 miles as part of your taper. The longest long run in a 12 week plan typically occurs in weeks 9-10 and should be 10-11 miles. You don't need to run the full 13.1 miles in training - race day adrenaline and taper will carry you through the extra miles.
Can I follow a 12 week half marathon plan as a beginner?
Yes, but you need some running base first. Before starting a 12 week half marathon plan, you should be able to comfortably run 3-4 miles without stopping. If you're starting from zero, complete a Couch to 5K program (8 weeks) first, then build to 10-12 miles per week (4 weeks), then start the 12 week half marathon plan. Total time from zero to half marathon: about 24 weeks.
How should I pace my long runs in a 12 week half marathon plan?
Long runs should be done at an easy, conversational pace - typically 1-2 minutes per mile slower than your goal race pace. For example, if you want to run your half marathon at 10:00/mile pace, your long runs should be at 11:00-12:00/mile. The purpose of long runs is building endurance, not speed. Going too fast increases injury risk and reduces recovery.
What if I miss a week of training in my 12 week plan?
Missing one week isn't the end of the world. If you miss 1-2 runs, just continue with your scheduled plan. If you miss a full week due to illness or injury, you have two options: (1) Add an extra week to your plan and repeat the missed week, or (2) Continue with the plan but reduce the mileage by 10-15% for the next week to ease back in safely. Don't try to "make up" missed mileage - this leads to injury.